docker build fails due to missing jb install

[evq]

jsonnet -S lib/rules.jsonnet > prometheus_rules.yaml
jsonnet -J vendor -m dashboards_out lib/dashboards.jsonnet
RUNTIME ERROR: couldn't open import "grafana-builder/grafana.libsonnet": no match locally or in the Jsonnet library paths.
        lib/../dashboards/k8s-storage-resources-glusterfs-pv.libsonnet:1:11-53  thunk <g>
        lib/../dashboards/k8s-storage-resources-glusterfs-pv.libsonnet:60:7     object <grafanaDashboards>
        lib/../dashboards/defaults.libsonnet:7:17-44    object <dashboards>
        lib/dashboards.jsonnet:4:11-27  object <anonymous>
        During manifestation
make: *** [Makefile:17: dashboards_out] Error 1